SDL: fixed build error due to -Wunused-function

SDL Commits
1 
From 77e59d4fa9aff581e0303cdbd68a5d0d08cfab9b Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <[EMAIL REDACTED]>
Date: Sat, 27 May 2023 18:56:10 +0300
Subject: [PATCH] fixed build error due to -Wunused-function

---
 src/hidapi/mac/hid.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/hidapi/mac/hid.c b/src/hidapi/mac/hid.c
index d646f7699e4c..13bd9b94a96d 100644
--- a/src/hidapi/mac/hid.c
+++ b/src/hidapi/mac/hid.c
@@ -214,6 +214,7 @@ static void free_hid_device(hid_device *dev)
 }
 
 
+#ifndef HIDAPI_USING_SDL_RUNTIME
 /* The caller must free the returned string with free(). */
 static wchar_t *utf8_to_wchar_t(const char *utf8)
 {
@@ -235,6 +236,7 @@ static wchar_t *utf8_to_wchar_t(const char *utf8)
 
 	return ret;
 }
+#endif
 
 
 /* Makes a copy of the given error message (and decoded according to the